In a wind turbine system, heat transfer between a power converter and a coolant typically occurs by advection as a result of the temperature differential that inherently exists in the system. Specifically, heat from the power converter is transferred to the circulating coolant, transforming it to its vapor phase. The heat is then extracted from the coolant vapor, which causes it to condense and turn back into its liquid phase. A coolant having a boiling point equal to or lower than the power converter's operating temperature is chosen in order to allow the above-described heat exchange cycle to happen.